Capillary fans



June 22, 1965 J. E. MCDONALD 3,190,544

CAPILLARY FANS Original Filed Aug. 16, 1962 United States Patent O 3,190,544 CAPHLARY FANS John lil. McDonald, Newton, Mass., assigner to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania @riginal application Aug. 16, 1962, Ser. No. 217,341, now Patent No. 3,i2ti,94, dated May 14, 1964. Divided and this application Mar. 26, 1964, Ser. No. 354,833 2 Claims. (Ci. 23h-134) This application is a division of my copending application, Serial No. 217,341, tiled August 16, 1962, now U.S. Patent No. 3,128,940.

This invention relates to capillary fans in which the movement of air is produced by rotating rings of brous material.

In air conditioning and other air handling units using centrifugal fans for moving air, and in which quietness of operation is more important than eiiiciency, it has been proposed to use rings of fibrous material such as so-called glass wool or bre glass on the rotors of centrifugal fans instead of the usual fan blades, and to support such rings along their entire axial lengths.

This invention uses as the air moving element of a centrifugal fan, an annular ring of sponge-like foamed plastic. By sponge-like is meant a three dimensional network of skeletal strands integrally joined together and forming therebetween voids which occupy the major portion of the volume air space of the foamed plastic. A preferred material is polyurethane foam, the advantages of which are its low cost, its being easily removable from a fan rotor when it has become clogged with dirt, its lack of break-up during handling and use, and its having sufficient stiffness, while it is resilient, to be largely self-supporting. An advantage over well known, so-called open cell urethane foam is that there are no membrane-like windows connecting the strands, and which would otter increased resistance to air iiow, and would prevent desired change of direction of air flow.

This invention also reduces the costs oi such rotors for double-inlet fans by supporting annular rings of iibrous material on the centerplates only of the rotors.

An object of this invention is to provide the rotor of a double-inlet centrifugal fan with an air moving element consisting of an annular ring of fibrous material.

Another object of this invention is to support an annular ring of brous material at its center on the center plate of a double-inlet fan.

Another object of this invention is to use an annular ring of sponge-like oamed plastic as the air moving rotor of a centrifugal fan having a double inlet.

This invention will now be described with reference to the annexed drawings, of which:

FIG. 1 is a side View, in section, of a rotor of a doubleinlet centrifugal fan embodying this invention, and

lwdd Patented! .lune 22, 1965 FIG. 2 is an end view of the rotor oi FIG. l.

The rotor has a centerplate 10 with an enlarged rim l1 having an inwardly curved outer edge 12, and has a hub 1&3. An annular ring 14 of polyurethane foam having an inner diameter smaller than the distance between diametrally opposite portions of the edge 12, is placed at its longitudinal center on the edge 12, and a plastic snap-ring 15, circular in section, is placed around the longitudinal center of the ring i4, deforming the latter so that its inner surface at the edge 12 is forced against the latter, and forming the sole means for supporting the annular ring 14 from the centerplate liti. The snap-ring 15 and the annular ring 14 are easily removable and replaceable.

The annular ring 14 has strands 16 which, during rotation of the rotor, change the direction of the air they impact, in the direction of rotation of the rotor, and cause air iiow in the usual centrifugal action. The air enters the open ends of the ring 14, and is turned radially as is usual in rotors of centrifugal fans.

The stiffness of the ring 14 is sutcient to prevent its requiring support along its entire length. Thus, the supporting structure for the ring 14 is simplier and less expensive than prior basket-litre supports which extend the full lengths of their associated annular rings, and the annular rings are easier to remove and replace than in prior constructions.

The centerplate of a double-inlet rotor is, of course, the backplate of each rotor section.

What is claimed is:

1. A rotor for a centrifugal fan having a double inlet, comprising a circular centerplate having a rim with an inwardly curved depression in its center, an annular ring of fibrous material having a central portion around said rim, and a snap-ring, circular in section, around said central portion and pressing the inner surface of said central portion into said depression.

2. A rotor tor a centrifugal fan comprising a circular plate having a rim with an inwardly curved `depression in its center, an annular ring of brous material having an inner portion around said rim, and a snap-ring, circular in section, around said portion and pressing the inner surface of said portion into said depression.

References 'Cited by the Examiner UNlTED STATES PATENTS 2,155,231 4/39 Hubbard et al ZBO-134.48 2,966,960 l/61 Rochlin 230-134 2,991,843 7/61 Bell 103-115 3,018,896 l/62 Gewiss 103-115 3,123,286 3/64 Abbott 55-400 JOSEPH H. BRANSON, JR., Primary Examiner. 

1. A ROTOR FOR A CENTRIFUGAL FAN HAVING A DOUBLE INLET, COMPRISING A CIRCULAR CENTERPLATE HAVING A RIM WITH ANWARDLY CURVED DEPRESSION IN ITS CENTER, AN ANNULAR RING OF FIBROUS MATERIAL HAVING A CENTRAL PORTION AROUND SAID RIM, 